A graphical user interface (GUI) application is one that is designed using graphical features such as windows, menus, dialog boxes, and features that make the application easy to use. When you compile a GUI application, an executable file with start-up code is created. The executable usually provides the basic functionality of your program, and simple programs often consist of only an executable file. You can extend the application by calling DLLs, packages, and other support files from the executable. 

The IDE offers two application UI models:

• Single document interface (SDI)
• Multiple document interface (MDI)

In addition to the implementation model of your applications, the design-time behavior of your project and the runtime behavior of your application can be manipulated by setting project options in the IDE.